Seminar

Asteroseismiology of Kepler Exoplanet Hosts

Speaker:Ashley Chontos

Date:October 5, 2017

Time:4:15 pm

Location:TBD

Host:Ruth Angus

Transits measure properties relative to the star, hence understanding stellar properties are important to characterize exoplanets. Asteroseismology is one of the best ways to determine fundamental stellar properties, calculating stellar radii and masses to within 3% and 5%, respectively. Therefore, planets orbiting seismic hosts are the best characterized systems to date. Recent studies have been done on seismic Kepler exoplanet hosts, with ~100 known to date. However in mid 2016, there was a re-release of short cadence data after a calibration error was noticed. Here we present the first, complete asteroseismic study of Kepler exoplanet hosts since the final release of short-cadence data. Preliminary results include 12 new seismic detections as well as previously known seismic hosts that do not appear to be oscillating using the new data. One new interesting seismic host, KOI-4, was so far believed to be a background eclipsing binary due to a deep secondary eclipse around what was thought to be a main sequence star. Our seismic analysis suggests that KOI-4 is an evolved subgiant with a Jupiter-sized planetary companion. TRES radial velocity measurements were able to confirm this hot Jupiter, which has an orbital period less than 4 days. Since the first three planets were known pre-launch, KOI-4 is the first planet Kepler found but one of the last planets to be confirmed.